What is a line? A segment? A ray? How are they different from the representations you were using?

Problem D3

What is a plane? How is it different from a sheet of paper?

Video SegmentIn this video segment, participants discuss some of the vocabulary of geometry. Watch this segment after you have completed Problems D1-D3 and compare your thinking with that of the onscreen participants.

What are some of the difficulties the participants ran into while trying to define a point and a line? How are your descriptions similar to or different from those of the onscreen participants?

If you are using a VCR, you can find this segment on the session video approximately 20 minutes and 48 seconds after the Annenberg Media logo.

Problem D4

What is a circle? Why is it impossible to draw a true circle?

Problem D5

Reflect on your learning of geometry in the past. What is geometry "all about"? What is important in becoming a successful learner of geometry?